The present invention relates to an industrial control system and, in particular, to a control system, method and program that increase availability of an industrial control system (hereinafter abbreviated as “ICS”).
ICSs are being used as control systems such as water supply management systems, nuclear power plant control systems and traffic monitoring/control systems, and are playing an important role in supporting social infrastructure such as water and electricity supplies and transportation. The social infrastructure using the ICSs has a great influence on people's lives. Accordingly, a much greater availability is required of the ICSs than is required of ordinary IT systems.
In the past, ICSs were isolated from external networks such as the Internet and other ICSs. However, in recent years, ICSs have been connected onto an external network so that multiple external systems use information from devices managed by the ICSs. Consequently, the ICSs have become vulnerable to attacks, such as malware attacks, through the external networks and there has been a growing demand for more enhanced availability of ICSs.
One example of an ICS is a computing system disclosed in Patent Literature 1, which determines estimated average speed information of a vehicle traveling on a road on the basis of data samples reflecting the travel on the road. In the computing system, multiple sensors are embedded in the road and traffic data samples are obtained from these sensors to determine the average speed of the vehicle.